What is IGCSE Biology?

IGCSE Biology is the study of living organisms and life processes, designed for international students aged 14–16. It explores topics from how your body fights disease to how ecosystems function, offering a globally recognised qualification valued by universities and employers in over 140 countries.

Offered by Cambridge International and Pearson Edexcel, IGCSE Biology sits alongside Chemistry and Physics as one of the three sciences. Unlike GCSE, which is mainly designed for UK schools, IGCSE is created for students all over the world. This means the courses use examples from many different countries and environments, making them more relevant to an international audience.

This qualification provides an excellent foundation for further study in biology and for science-related careers.

What will you study in IGCSE Biology?

While exact details vary, the big ideas covered in biology at IGCSE are the same across the different specifications; essential topics include:

• characteristics of living organisms: basic life processes, including movement, respiration, sensitivity, growth, reproduction, excretion, and nutrition

• cell structure and organisation: plant, animal, and bacterial cell structure, organelle functions and levels of organisation, from organelles to organ systems

• movement of substances: diffusion, osmosis and active transport, and factors affecting the rate of movement

• biological molecules and enzymes: structure and testing of carbohydrates, proteins, and fats, as well as enzyme function and the effects of temperature and pH on enzyme activity

• nutrition in plants and humans: photosynthesis, limiting factors and leaf adaptations in plants, and components of a balanced diet and digestive system function in humans

• transport systems: xylem and phloem in plants and the circulatory system in animals, including the heart, blood vessels, and blood components

• gas exchange in humans: structure of the breathing system, adaptations of gas exchange surfaces, and the effects of exercise on breathing

• respiration: aerobic and anaerobic respiration, and the use of energy in living organisms

• excretion: excretory products and the roles of the lungs, kidneys, and skin

• reproduction: differences between asexual and sexual reproduction, and reproduction in plants and humans, including fertilisation, reproductive systems, and hormonal control

• diseases and immunity: pathogens, disease transmission, body defences and the role of hygiene in disease prevention

• ecology and environment: key ecological terms, food chains and webs, the carbon cycle, and human impacts such as pollution and deforestation

Have a look at our IGCSE exam topic articles for more details on the topics covered in IGCSE Biology:

• IGCSE Biology Topics by Exam Board: Full List

• IGCSE Science Topics by Exam Board: Full List

Core vs Extended tier

In IGCSE Biology, content is split into two difficulty levels, known as Core and Extended tiers. Some schools only offer one tier to all students, while others may allocate students to tiers based on class performance and test results.

Some students may have the option to choose which tier they study; in this situation, your teacher will be able to guide you towards the option that best suits your ability, confidence, and future plans.

• Core tier: covers the essential biology content at a simpler level. You'll study all the main topics but with fewer complex examples and less challenging applications. The maximum grade available is a C (or 4 in the 9–1 system), with grades ranging from C to G (4–1).

• Extended tier: includes everything from the Core syllabus, plus additional content and greater depth. You'll face more detailed questions and be expected to apply your understanding to unfamiliar scenarios. This tier allows access to the highest grades, from A* to G (or 9 to 1).

Most students aiming for A Level Biology or science-related courses choose, or are recommended for, the Extended tier, as it offers better preparation for further study. If you’re unsure which tier is right for you, speak with your science teacher — they’ll help you decide, based on your learning style and future goals.

How is IGCSE Biology assessed?

Assessment methods differ slightly between exam boards, but key features are consistent:

• Cambridge IGCSE Biology

  • Paper 1: Multiple choice – 45 mins, taken by all students

  • Paper 2: Core theory – 1 hr 15 mins, Core tier students only

  • Paper 3: Extended theory – 1 hr 15 mins, Extended tier students only

• Edexcel International GCSE Biology

  • Paper 1: 2 hours – full syllabus

  • Paper 2: 1 hr 15 mins – practical skills and applications

Both exam boards include multiple-choice, structured, and extended response questions.  Practical skills are assessed through written questions about experiments rather than separate practical exams; you'll need to analyse data, suggest improvements to methods, and explain experimental designs.

IGCSE Biology vs GCSE Biology

The differences between IGCSE and GCSE Biology explain why many international schools choose IGCSE.

The choice between IGCSE and GCSE usually depends on your school type rather than personal preference; international schools typically offer IGCSE while UK state schools offer GCSE.

What skills will you develop in IGCSE Biology?

IGCSE Biology supports both scientific understanding and a wide range of transferable skills, including:

• scientific literacy: understanding everyday processes like immunity, diet and health, and environmental issues

• data analysis: interpreting graphs, tables, and experimental results

• critical thinking: evaluating evidence, comparing theories, and questioning assumptions

• communication: developing precision in written explanations and using correct scientific terms

• problem-solving: applying biological knowledge to unfamiliar or real-world scenarios

• Scientific method: understanding experimental design and how investigations are structured

From my experience supporting students into A Level and beyond, those who fully engage with data analysis and experimental design skills find the transition to higher-level science much smoother.

How to do well in IGCSE Biology

Use active revision techniques

Active methods are more effective than passive re-reading; some examples of active revision techniques include:

• use flashcards to memorise key terms and definitions.

• practice quizzes—either on your own or with a group—to strengthen retrieval

• teach someone else — explaining topics aloud reveals what you truly understand.

• schedule regular short review sessions to keep content fresh. 

Consider making use of revision resources from Save My Exams, which include detailed revision notes, practice questions, flash cards and mock exams tailored to different IGCSE exam boards. Our IGCSE Biology resources are written by experienced teachers who understand exactly what students need to succeed.

• Cambridge IGCSE Biology Revision

• Edexcel IGCSE Biology Revision

Practise past papers early

Past papers provide the best exam preparation available, so start practising with exam questions early in your course, not just before exams. This familiarises you with question styles and helps identify knowledge gaps while there's still time to address them. When working through past papers it can be a good idea to:

• use mark schemes to understand how answers are graded.

• build time management skills by practising under timed conditions.

• check your answers straight away to correct misunderstandings early. 

Having marked countless practice papers, I’ve noticed that students who learn how to ‘think like an examiner’ — by checking the mark scheme as carefully as the question itself — consistently achieve higher grades.

Learn command words

IGCSE Biology uses specific command words that tell you exactly what examiners expect your answer to contain.  Common examples include:

• describe: state what happens — no explanation required

• explain: give reasons using scientific knowledge

• compare: identify similarities and differences

• evaluate: weigh up pros and cons, or strengths and limitations

One of the most common reasons students lose marks is misunderstanding or ignoring command words. I regularly train my classes to highlight these words before answering, a simple habit that often boosts marks.

Build practical understanding

Although you won't sit separate practical exams, practical knowledge appears throughout written papers, so it is a good idea to:

• know methods and results for core experiments, e.g. food tests, osmosis investigations

• practice interpreting data and identifying trends

• be prepared to plan experiments, identify variables, and suggest improvements

Is IGCSE Biology right for you?

Consider these questions to help decide whether IGCSE Biology suits your interests and goals:

• Do you enjoy learning about living organisms and how they function?

• Are you confident in reading and understanding scientific explanations?

• Do you want to study Biology or medical science at A Level or university?

• Are you interested in careers in health, research, or environmental fields?

• Can you balance memorising facts with understanding biological processes?

If you answered "yes" to most questions, IGCSE Biology could be an excellent choice. If you're unsure, speak with your science teachers about your interests and career aspirations.

Frequently asked questions

What is the difference between Core and Extended IGCSE Biology?

Core tier covers essential content with less depth and allows students to access grades C–G or 4–1. Extended includes everything from Core plus more advanced material; students can be awarded grades A*–G or 9–1. Extended tier students typically find A Level Biology more manageable due to stronger preparation.

Can I take IGCSE Biology without Triple Science?

Yes, IGCSE Biology can be taken without studying triple science. While some schools require all students to study separate sciences (Biology, Chemistry, Physics), others allow flexibility; students may choose their favourite science rather than taking all three, while some may have the option to study coordinated (double award) or combined science (single award).

Do I need IGCSE Biology for A Level Biology?

Most schools require IGCSE Biology (or equivalent) with grade B/6 or above for A Level Biology entry. University admission statistics show that students without strong IGCSE Biology backgrounds struggle significantly with A Level content.

Is Cambridge IGCSE harder than Edexcel?

Both exam boards maintain similar standards and difficulty levels. Cambridge tends to use slightly more direct questioning, while Edexcel often includes more contextualised scenarios. Student outcomes are typically comparable.

How long does the IGCSE Biology course take?

IGCSE Biology typically takes two years when started in Year 10 (age 14-15). Some schools offer accelerated one-year courses for older students, while others spread learning over three years starting in Year 9.

Final thoughts

IGCSE Biology is a valuable, internationally recognised qualification. Whether you're planning university study, exploring career options in science, or simply satisfying scientific curiosity, this course provides excellent foundations.

Success in IGCSE Biology relies on genuine interest and consistent effort; start building effective study habits early, engage with the practical work, and don't hesitate to ask questions when concepts seem unclear. With the right approach and genuine curiosity about life sciences, IGCSE Biology can be both fascinating and rewarding. 

Explore Our IGCSE Biology Resources